The West London club had an initial proposal of £4.5million rejected by the Hoops but have since returned with a fresh bid according to Mjallby who is unsure of what the future holds for the prolific 25-year old striker.
"A bid came in last night," Mjallby told reporters on Tuesday. "I don't know how the club has responded to it.
"They increased the bid a wee bit when it came in yesterday. If it is good enough, I don't know. That's something you have to ask the chief executive, the manager and the board.
"We know it looks likely right now that Gary is going to leave the club. I'm not too sure the final word has been said yet. We have to wait and see.
"I think the club is going to sit down and think about it. If he has played his last game, I don't know."